From 32be32509987fbe42cf5c2fd3cea3c2ad6eae179 Mon Sep 17 00:00:00 2001 From: Rob Bradford Date: Tue, 18 Jul 2023 14:11:44 +0100 Subject: target/riscv: Fix LMUL check to use VLEN MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The previous check was failing with: VLEN=128 ELEN = 64 SEW = 16 and LMUL = 1/8 which is a valid combination. Fix the check to allow valid combinations when VLEN is a multiple of ELEN. From the specification: "In general, the requirement is to support LMUL ≥ SEWMIN/ELEN, where SEWMIN is the narrowest supported SEW value and ELEN is the widest supported SEW value. In the standard extensions, SEWMIN=8. For standard vector extensions with ELEN=32, fractional LMULs of 1/2 and 1/4 must be supported. For standard vector extensions with ELEN=64, fractional LMULs of 1/2, 1/4, and 1/8 must be supported." Elsewhere in the specification it makes clear that VLEN>=ELEN. From inspection this new check allows: VLEN=ELEN=64 1/2, 1/4, 1/8 for SEW >=8 VLEN=ELEN=32 1/2, 1/4 for SEW >=8 Fixes: d9b7609a1fb2 ("target/riscv: rvv-1.0: configure instructions") Signed-off-by: Rob Bradford Reviewed-by: Weiwei Li Message-Id: <20230718131316.12283-2-rbradford@rivosinc.com> Signed-off-by: Alistair Francis --- target/riscv/vector_helper.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'target') diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c index cfacf2e..4d06754 100644 --- a/target/riscv/vector_helper.c +++ b/target/riscv/vector_helper.c @@ -43,9 +43,9 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1, xlen - 1 - R_VTYPE_RESERVED_SHIFT); if (lmul & 4) { - /* Fractional LMUL. */ + /* Fractional LMUL - check LMUL * VLEN >= SEW */ if (lmul == 4 || - cpu->cfg.elen >> (8 - lmul) < sew) { + cpu->cfg.vlen >> (8 - lmul) < sew) { vill = true; } } -- cgit v1.1